Synopsis The aircraft had struck trees in rising terrain, at an elevation of about 1,150 feet asl, and came to rest in a canola field. There were low stratus cloud ceilings and heavy fog in the area of the occurrence. The pilot, who was the sole occupant, was not wearing a shoulder harness and was fatally injured in the accident. Other Factual Information The pilot had been a licensed pilot since 1971. He obtained his first instrument rating in 1976, and a class III instructor rating in 1978. The pilot was active in aviation as a flight instructor and a charter pilot, and accumulated about 1,542 flying hours from 1976 to 1979. By 1979, the pilot had 11 hours of instrument flying, 53 hours of simulated instrument flying, and 32 hours in a training simulator. In the 15-year period between 1980 and 1995, the pilot had flown an additional 55.2 hours. In the three months preceding the accident, the pilot had flown nine hours, including one hour of instrument flying in a Cessna 310 aircraft, and 2.2 hours in a Link simulator. In June 1991, the pilot consulted his family physician after experiencing dizziness, visual disturbance, and numbness in his left hand, nose, and upper lip, followed by a headache. An electroencephalogram (EEG) was performed on 19June 1991, and the results were normal. On 22October 1991, a consultation was made with a neurologist, who diagnosed the condition as a migraine. On 30November 1991, the family physician noted that the pilot experienced a further episode of visual disturbance, right hand numbness, and headache. The diagnosis of this episode was also migraine. There is no further evidence of headaches between November 1991 and 28July 1995. This medical condition could result in a sudden decrement in performance or in complete incapacitation. The pilot did not disclose this medical information on any of his aviation medical examinations. If this information had been reported during his aviation medical examination, it likely would have resulted in his pilot privileges being revoked. Whether the pilot was suffering from a migraine headache or any of the associated symptoms at the time of the accident was not known. The aircraft was a twin-engine Cessna 310. There was no evidence of any aircraft failure or malfunctions prior to the collision with the trees and ground. Analysis of the recorded radar information shows that the aircraft descended from level flight at 4,500 feet asl to 1,500 feet asl in about 1 minute 45 seconds, about 1,700 feet per minute. The rate of descent was fairly constant throughout. Recent changes to the Air Navigation Orders (ANO Series II, No.2/CRCc.-28, Order Respecting Aircraft Seats and Safety-Belts) required commercial aircraft to be outfitted with shoulder harnesses for the front-seat occupants. The aircraft owner had applied for, and been given, a temporary exemption to the requirement. When the aircraft was examined, shoulder harnesses were installed in the aircraft. The log-book entries regarding the installation were not certified in an approved manner. The shoulder harness was a fixed type, not an inertial reel type. If the fixed type shoulder harness was used and properly adjusted across his chest, the pilot could not lean forward and reach various switches and items in the cockpit without first loosening the shoulder harness. On the day of the accident, a weak frontal trough was situated between Muskoka and Kingston by 0700 EDT. The air mass over the region was very moist, and after 0600 EDT, fog and low cloud began to form. The moist south to southeasterly upslope flow resulted in low stratus cloud ceilings from the surface to 500 feet above ground level (agl), and visibilities of one half mile or less in the vicinity of the accident site. Before departing from Lindsay, the pilot phoned the Sault Ste. Marie Flight Service Station and received a weather briefing. The briefing included thunderstorm and turbulence warnings in the Georgian Bay area, and warnings of reduced visibilities in fog for southern Ontario. Clear weather conditions were forecast for the central Ontario regions, including Lindsay. As part of the briefing, the pilot was told that visibility in Kitchener was three miles in fog, and that London had two and a quarter miles in fog. The reported cloud conditions were 9,000 feet scattered in Kitchener and 11,000 feet broken in London.